Silica behavior in the alumina carbothermic reduction-chlorination process

The behavior of silica was investigated experimentally in an alumina carbothermic reduction process and chlorination process in vacuum. The results showed that, first, SiC was produced by SiO2 and C, and then Al4SiC4 was produced by Al4C3, Al4O4C, C, and SiC during the alumina carbothermic reduction process at about 1,763 K. C, Al3C4 and Al4O4C decreased and Al4SiC4 increased as content of SiO2 increased. The following chlorination process was blocked, and the recovery rate of aluminum decreased quickly compared with that without silica. It was inferred that silica might be unfavorable for aluminum extracted from alumina by carbothermic reductionchlorination process in vacuum at about 1763 K.